1. Field of the Invention
This invention relates to an airsoft gun, more particularly to a spring-piston airsoft gun.
2. Description of the Related Art
Airsoft guns used for recreation are generally powered by a piston compressing a pocket of air, and are classified into three types: gas-powered airsoft guns, spring-power airsoft guns, and automatic electric guns. Spring-powered airsoft guns and automatic electric guns are more popular in combat simulations and war games because they are safer.
Referring to FIG. 1, a conventional airsoft gun is shown to include a piston 12 which is loaded with a coil spring 13 and which is manually or automatically pulled backward to a rear chamber of a barrel 11 to compress the coil spring 13 to thereby cock the gun for firing. To stabilize expansion of the coil spring 13, an anchor member 14 is provided, which extends forwardly from a rear-gun end. A rear portion of the coil spring 13 is securely sleeved on the anchor member 14 such that, when the gun is triggered, the coil spring 13 is released to expand so as to drive the piston 12 forward, and the piston 12 in turn forces compressed air in the barrel 11 through a muzzle 15, thereby propelling plastic pellets (not shown). The anchor member 14 may be in the form of a shank 141, as shown in FIG. 2. The coil spring 13 is liable to seriously impact the shank 141, thereby causing great noises, wearing and heating of the shank 141, and twisting and deformation of the coil spring 13, which will in turn result in damage to the piston 12.
Referring to FIG. 3, another anchor member is proposed, which includes a shank 141 and a plastic sleeve 143 rotatably sleeved on the shank 141 so as to be rotated with the coil spring 13 to thereby minimize friction therebetween. However, no wear-resistant means is provided at two ends of the sleeve 143 where friction between the coil spring 13 and the sleeve 143 is relatively large.